It is known that water-containing dentifrices which include strontium and sequestering agents such as EDTA are effective in the treatment of hyper-sensitive dentin, gingivitis and periodontitis, apparently through the mechanism of substituting strontium for calcium in the calcium hydroxy apatite of the tooth (Schole et al U.S. Pat. No. 3,699,221 and 3,988,434).
It is also known that ricinoleic acid and various esters and salts which are surface active agents exhibit a higher contact angle with tooth enamel than other surface active agents.